NUCLEAR CHEMISTRY

Isotopes atoms of the same element with different numbers of neutrons

What is a Radioactive Isotope? an isotope of an element having an unstable nucleus it decays by gaining or losing protons and/or neutrons Any atom containing 84 or more protons is radioactive

Penetration of Radiation

Alpha Radiation ( α ) α 2 protons and 2 neutrons (Helium nucleus) α The element " transmutes " into another element α atomic number decreases by 2 α Mass number decreases by 4 (2 protons + 2 neutrons) α Have a +2 charge α Have the greatest mass α Do not travel very far α Can not pass through our skin α Can cause harm inside body Alpha Radiation from Plutonium in lung tissue

Beta Radiation ( β ) β The emission of electron(s) from the atom's nucleus β Have a -1 charge β Can penetrate the skin to the germinal layer β Most can be stopped by light clothing β Can be harmful inside the body

Gamma Radiation ( γ ) Waves of UV light energy from the nucleus of an atom Can travel far distances No charge or mass Most useful type of radiation for medical purposes, but most dangerous because of its ability to penetrate large thicknesses of material

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Radioactive Half-life The time for half the radioactive nuclei in a sample to undergo radioactive decay.

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Half-Life Problems A radioactive isotope has a ½ life of 30 minutes. If we have 6mg at 12:00pm, how much will be left at 2pm? – 0.375mg Suppose we have 40mg of a radioactive isotope at 8am and only 5mg at 8:45am. What is the ½ life of the isotope? – 15 minutes